Super Galaxy

The upgrade resulted from studies in the late 1990s that showed that despite more than 80 per cent of the C-5 fleet’s projected airframe life remaining, the USAF was seeing critical shortfalls in aircraft availability due to outdated hydraulics, avionics and other key systems. Further, the original GE TF39 engines, which in fact were the first production high bypass turbofans, were becoming increasingly difficult to support and were far less efficient than modern engines.

Big lifter

The C-5A resulted from the USAF’s 1961 CX-HLS requirement for a heavy jet transport with a cargo bay larger than that of the C-141 Starlifter then entering service and the older C-133. Lockheed’s design was selected as the winner in 1965, and the first of 81 C-5A Galaxies entered service with the USAF in December 1969.

Then the largest aircraft in the world, the USAF placed restrictions on the C-5A’s lifting capacity in the late 1970s following the discovery of cracking in the wings, a problem not remedied until the aircraft were given new wings from 1981 to 1987 featuring stronger alloys not available during the original production run. In addition to the C-5A re-wing program, the Galaxy production line was re-opened in the 1980s and a further 50 C-5Bs featuring the new wing design and uprated TF39-C1 engines were built between 1984 and 1989.

Two C-5As were also modified as C-5Cs, which are specially configured to support the US space program. They had the rear upper passenger deck removed, and are fitted with a moveable aft bulkhead and other specialised handling equipment for carrying rocket stages and satellites.

Thirteen C-5As were retired to desert storage with AMARG at Davis Monthan AFB in 2005, while one was sent to the USAF’s Warner Robbins Air Logistics Center where it was torn down and inspected to establish the type’s remaining fatigue life.

AMP & RERP

The first stage of the upgrade has seen or will see all C-5A, B and C models receive new cockpits with a digital flight control system and autopilot, new GATM (global air traffic management) system compliant communications and integrated datalink capabilities, plus EFIS glass displays, EGPWS (enhanced ground proximity warning system), and other navigation and safety equipment upgrades. Most impor-tantly though, AMP provides the digital backbone for the more comprehensive RERP upgrade. The first AMP C-5 was redelivered in 2002, and all 111 aircraft the USAF intends to retain in the short to medium term are scheduled to receive the upgrade by 2014. Most of the work is being performed during maintenance periods at Dover and Travis AFBs by USAF and Lockheed Martin personnel, and each AMP kit costs about US$6 million per aircraft installed.

The second major stage of the program is the Reliability Enhancement and Reengining Program, or RERP, which sees the replacement of the ageing TF39s with more modern GE CF6-80C2 turbofans. With the military designation F108-GE-100, these engines have not only proven to be more reliable, but also far more efficient. The CF6 produces more than 50,000lb (222kN) thrust compared to the TF39’s 41,000lb (183kN), and is Stage 3 noise compliant.

The increased thrust allows for shorter takeoffs, higher payloads and weights, and substantially increases range.

“The CF6 is a 60,000lb thrust engine derated to 50,000lb, so we’ve basically added 22 per cent more thrust to the aircraft,” said Lt Col Mike Semo, head of the C-5M integration office at Dover AFB. “Now we can take off at higher weights – from 769,000lb (349,000kg) to 840,000lb (381,000kg) which was actually our previous emergency wartime weight – it’s fantastic!” Other improvements have been made to the aircraft’s complicated landing gear and bays, its troublesome hydraulics and the flap and slat system, an embedded diagnostic system was added, the wiring loom was renewed, and another 50 or so discreet components and systems changed, almost all aimed at increasing reliability and making maintenance far easier.

The RERP process is a much more complicated and invasive one than AMP, and costs in the region of US$80 million per aircraft to complete, and the C-5s are required to enter a production line at Lockheed Martin’s Marietta, Georgia, facility for a complete strip down and virtual rebuild. Currently a RERP can take 12 months to complete, but Lockheed Martin expects to get this figure down to eight months once full rate production commences in 2012. The USAF has plans to put 52 C-5s through the RERP process – the original C-5A proof of concept aircraft, the two C-5Cs, and all 49 C-5Bs that remain in service.

Despite interest from the USAF, there are currently no plans to put any of the C-5A fleet through RERP, as the medium to long term future of some or all of these aircraft is not yet assured. There has also been talk in some quarters about transferring some of the C-5As to the US’s Civil Reserve Air Fleet for use as civil outsized airlifters which can be called up for military duty in an emergency. “There was some talk about that, it’s just one option among many,” said Lt Col Semo. The Air Force has stated that they are intending within the next few years to retire 22 C-5As to meet the requirement for 316 strategic airlifters, but as to what those aircraft will be doing after that has not been determined. ”

Improvements

During a surge conducted in late 2009 of the first three low rate production C‑5Ms, the aircraft demonstrated they could fly more than 900nm further than a non upgraded Galaxy with a 45 tonne payload, and 2100nm further than a C-17; that it can fly 50 per cent further than a C-17 with double the volume load; that it uses 40 per cent less fuel than an older C-5 carrying the same load the same distance; that for a typical 4200nm mission it requires 1645m of runway to get airborne compared to 1920m for an earlier model Galaxy; and that it costs 35 per cent less than a C-17 to carry a pallet of cargo on a typical mission.

Lt Col Semo explained that the type qualification time for a C-5A/B pilot to the C-5M is quite minimal. “For the pilots it takes two days of academics, five simulator rides, and three flights, and for air-to-air refuelling quals we add on a further three flights. Pilots then require a check mission before we send them out in command of the aircraft. For flight engineers it’s a little longer – it’s a week of academics, a week of simulators, two weeks of flying training, and two missions to get the them qualified. ” He added that all C-5M pilots will initially be converted from the C-5A/B pool until about 2012 by which time there will be sufficient airframes to begin taking new pilots straight out of training.

Despite the cost associated with the upgrade, the USAF expects to recoup this and more throughout the life of the C‑5Ms through the increased efficiency of the new aircraft.

“The aircraft had over 40 years of airframe life left, and now we expect to fully realise that with these engines and improvement,” explained Lt Col Semo. “We expect to be able to fly the B models into 2050, so that’s where we’re getting our cost savings from being able to extend it and not have to replace it. An example of some of the in-service savings include – the B model engines currently need to be taken off the wing every 2000 hours, whereas a CF6 will be over 10,000 hours on wing, so right there you have huge maintenance savings. ” One of the major tests of the C-5M’s improvements was a surge of the first three airframes then in service in August and September 2009, which provided levels of availability unheard of in the C-5A/B world.

“We did 33 missions in 30 days from Dover to Incirlik (in eastern Turkey) with only three test aircraft,” explained Lt Col Semo. “One of those aircraft spent more time in the air over those 30 days than it did on the ground, and we did the entire surge with no air refuelling either. So originally was what designed as a reliability program has added a whole lot more capability as well. If we can take more cargo further downrange and transfer that into a C-17 or a C-130 – every hour we push forward, allows two hours less time in transit for a C-17, which allows the C-17s to be more efficient as well as us. ” Previously, regular C-5A/B operations from Dover to Incirlik had a stopover at Moron in Spain or another base en route, or an air-to-air refuelling. “We can actually go from Dover to Baghdad if we need to, but we haven’t exercised that,” he added.

“We’re really changing the doctrine of strategic airlift. We won’t change the crew aspect, but we will change the staging aspect and how far we can take the aircraft downrange. It really gives the national command authority more options. ” Apart from the major improvements made under AMP and RERP, crew comfort has also been taken into account, so the C-5Ms will also receive an interior refurbishment while undergoing maintenance at Stewart AFB in New York.

The interior work includes new sound absorption material, paint, floor coverings, kitchen and lavatories, LED lighting in the cockpit, crew rest and passenger cabins and in the cargo hold, and new seat coverings in the crew rest compartment. As Lt Col Semo explained, this has been very well received by crews. “It was actually one of our recommendations as aircrew – if we’re going to fly it for the next 40 years an interior refurb would be nice. It creates a nicer environment for the crew, especially on those long crew duty days. It helps gives the airplane that new car smell. ” And in an era where major project delays and budget blowouts are the norm, the AMP and RERP programs have remained on track and under budget throughout.

“I think this is because it’s a very cooperative effort,” said Lt Col Semo in closing.

“We are always reaching out to the contractor to make the aircraft better. And they’re always coming back to us on time, we work closely with the engineers and the business manager. So I would say the teamwork is what has kept this on time and made it successful – I would call this a model program for the way we should work together to get something done. I’ve got to give a lot of credit to the contractor – the trust of the individuals has worked to make sure everything gets done on time. ”